KHOBAR, Saudi Arabia, April 24 (Reuters) - Canadian engineering and construction company SNC-Lavalin Group Inc won a contract from Saudi Aramco for initial engineering and design work to expand the gas-oil separation plant of the Berri oilfield, industry sources said.

Saudi Aramco and SNC declined to comment.

The sources did not give a value for the contract.

Sources told Reuters in February Aramco would over time add 250,000 barrels per day of crude oil from Berri, possibly by building drilling islands offshore in the Gulf.

Companies bid for several packages of front-end engineering and design work on the project, which one source estimated could cost $6 billion in total.

Two sources told Reuters the estimated cost of the gas-oil separation plant expansion alone is about $1.7 billion.

Front-end engineering typically takes as long as a year to complete from the day of the award of contracts.

Saudi Aramco has said it will continue oil investments to maintain capacity. (Reporting by Reem Shamseddine; additional reporting by Allison Lampert; Editing by Adrian Croft)